Medical and/or dental instrument with a pneumatic oscillatory-drive

ABSTRACT

The invention relates to a medical or dental-medical treatment instrument ( 1 ) having a rod-like handpiece ( 2 ) with the forward end region of which a tool ( 3 ) can be releasably coupled by means of a tool coupling ( 4 ), and the rearward end region of which can be releaseably coupled with a connection part ( 6 ) by means of a handpiece coupling ( 5 ), preferably a plug-in/turn coupling, the handpiece having: a grip sleeve ( 11 ) which forms an outer body of the handpiece ( 2 ), an oscillatory rod ( 13 ) which extends longitudinally in the grip sleeve ( 11 ) and is mounted therein radially or also axially elastically yieldingly, an in particular pneumatic oscillation generator ( 31 ) for transmitting oscillations to the oscillatory rod ( 13 ), and a sleeve ( 14 ) surrounding the oscillation generator ( 31 ). For reducing noise emissions, the sleeve ( 14 ) is of elastically compressible or sound-absorbing material.

TECHNICAL FIELD

The invention relates to a medical or dental-medical instrument with apneumatic oscillatory drive.

BACKGROUND

In medical or dental-medical technology, a treatment of the human oranimal body, or artificial parts thereof (prostheses) can be effectedwith a tool of a treatment instrument in various ways. In many casesthere is necessary merely a treatment of the body without alteration ofits shape. Here, there may be involved e.g. a surface treatment in themanner of a massage. Another kind of treatment consists in altering theshape of the body, such as is the case e.g. with a material removingworking. With treatment instruments of the kind concerned, appropriatelydesigned, the tool is set into oscillation by means of an oscillatorydrive the frequency of which lies in particular in the sonic orultrasonic range. In particular when the oscillatory drive has anoscillatory element which transfers its oscillations to an oscillatoryrod by means of impact against the oscillatory rod, there is generated aconsiderable operating noise which is emitted both directly from theoscillatory drive to its surroundings or emitted from the oscillatoryrod or tool to the surroundings as solid-borne sound. The operatingnoise is in particular considerable and disturbing when the oscillatorydrive is a pneumatic oscillation generator. Such a treatment instrumentis known as a plaque removal device. In DE 197 51 682 A1 there isdescribed such a treatment instrument having a pneumatic oscillatorydrive for a material removing tool which is equipped for workingcavities. For the purpose of noise reduction, the oscillation generatoris surrounded by a sleeve of steel.

SUMMARY OF THE DISCLOSURE

The object of the invention is, with a treatment instrument of the kindsindicated in the introduction, to reduce noise emission.

With the disclosed treatment instrument, the sleeve is of elasticallycompressible or sound absorbing material, e.g. of sound-soft material.By these means there is attained a significant increase of the sounddamping. This is due to the fact that the sleeve does not merely form abarrier to sound but the sound is additionally damped at the elasticallycompressible or sound absorbing material of the sleeve, which isattained through the elastic yieldability or absorption capability ofthe inner surface of the sleeve, which is impacted by the sound, andthrough the elastically yieldable or sound absorbing material overall.The configuration in accordance with the invention has a constructionwhich is simple and economical to manufacture since the sleeve can bemanufactured in a simple and economical manner from rubber or plastics,and also a mounting or dismounting of the sleeve is without problem.

It is advantageous to radially support the sleeve on the inner surfaceof the grip sleeve. This leads to a simple and reliable supporting ofthe sleeve, whereby due to the elastically yielding material a directnoise transmission to the grip sleeve does not take place to the extentthat it does with steel sleeves. That is, the configuration inaccordance with the invention leads also in this respect to a noisedamping. For further noise damping it is advantageous to provide, in theaxial region of the oscillation generator, an annular spacing betweenthe inner surface of the grip sleeve and the outer surface of thesleeve, whereby as a result of the air gap thus formed the noise dampingis further improved.

The configuration in accordance with the invention is excellently suitedin combination with a further inner sleeve, which is surrounded by thesleeve of elastically compressible material. Thereby it is furtheradvantageous to provide an annular spacing between the sleeve and thefurther inner sleeve, for the purpose of additional noise damping. Theinner sleeve may be of hard material, e.g. of corrosion resistantmaterial, in particular steel.

Due to the elastically compressible material, the sleeve in accordancewith the invention is also excellently suited for the mounting of theoscillatory rod and/or the inner sleeve. By this means a particularlysimple configuration is attained, since additional bearing rings ofelastically compressible material are not necessary, the sleeve inaccordance with the invention assuming this function.

A comparable noise problem is present, with a treatment instrument ofthe kind concerned, in the region of the tool coupling between the tooland the oscillatory rod. Here it is to be emphasized that a noisedamping is already achieved if only the grip sleeve, which is of rigidor hard material, in particular corrosion resistant steel, and/or onlythe sleeve, preferably radially supported on the inner surface of thegrip sleeve, of elastically compressible or sound absorbing material,projects over the tool coupling. With the latter configuration the sounddamping is increased since the elastically compressible or soundabsorbing material in the sleeve leads to a stronger sound damping. Itis of particular advantage when both the grip sleeve and also the sleeveof elastically compressible or sound absorbing material project over thetool coupling. By these means, a maximum damping effect is achieved.Furthermore, at the same time a bearing function and a noise reductionfunction or noise damping function are fulfilled. The grip sleeve and/orthe sleeve may extend approximately up to the sickle-shaped outward bendof the tool and thereby project over the tool coupling and a part of thetool shaft. With this configuration, the noise emission in the region ofthe tool coupling and the region of the tool shaft concerned is reducedin that the grip sleeve and/or the sleeve acts against radial emissionof sound waves and thereby reduces the operating noise.

With the known configuration according to DE 197 51 682 A1, althoughthere is provided a sleeve of elastically compressible material, whichprojects over the grip sleeve, this sleeve does not project over thetool coupling and furthermore the sleeve is supported at its forward endradially on the oscillatory rod, whereby the oscillation of theoscillatory rod is affected.

With an advantageous development of the invention, the sleeve extendsfrom the forward end of the handpiece so far rearwardly that itsurrounds the oscillation generator. By these means, the elastic sleevefulfils not only a bearing function but also a noise damping function inthe longitudinally region from the tool coupling to the oscillationgenerator, whereby it contributes to even more effective noise reductionor noise damping.

The noise damping can be further improved in that the inner surface ofthe grip sleeve and/or of the sleeve-like bearing element has a shapingwhich reflects the sound inwardly.

Within the scope of the invention the longitudinal section of the gripsleeve and/or of the sleeve, projecting over the tool coupling, may beformed by means of a one-piece extension or by means of the forward partof a transversely separable grip sleeve and/or sleeve, whereby theforward part is connected with the remaining part by means of releasablecoupling and is thus releasable, e.g. for the purpose of cleaning of theforward end region or for the purpose of exchange for a differentforward sleeve part, which e.g. may be adapted to the shape and/ordimension of another tool, e.g. may be formed with different length.

Further which further improve the noise reduction and lead to simple,small and economically manufactureable constructions, which canadvantageously be integrated into a handpiece and moreover ensure asimple and rapid mounting or demounting.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the invention and further advantages which can be achievedthereby will be explained in more detail with reference to advantageousconfigurations of exemplary embodiments. There are shown:

FIG. 1 is an axial sectional view of a treatment instrument inaccordance with the invention;

FIG. 2 is a left end view of the treatment instrument of FIG. 5;

FIG. 3 is a plan view of the treatment instrument of FIG. 1;

FIG. 4 is a side view of a sleeve-like bearing part of elasticallycompressible material of the treatment instrument of FIG. 1;

FIG. 5 is a sectional view of the forward end region of a treatmentinstrument with an oscillation diagram;

FIG. 6 is an enlarged sectional view of an alternative oscillatory rodof the treatment instrument;

FIG. 7 is an enlarged sectional view of a further modified oscillatoryrod;

FIG. 8 is an enlarged sectional view of a forward end region of anothermodified treatment instrument in accordance with the invention;

FIG. 9 is an enlarged sectional view of a forward end region of anothermodified treatment instrument in accordance with the invention;

FIG. 10 is an enlarged sectional view of a forward end region of anothermodified treatment instrument in accordance with the invention; and

FIG. 11 is an enlarged sectional view of a forward end region of anothermodified treatment instrument in accordance with the invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The treatment instrument, designated overall as 1, includes a rod-likehandpiece 2, preferably extending in a straight manner, and a tool 3which is connected with the forward end region of the handpiece 2 bymeans of a releasable tool coupling 4 and forwardly projects from thehandpiece 2. The rearward end of the handpiece 2 is releaseablyconnected with a connection part 6 of a flexible supply line 7 by meansof a releasable handpiece coupling 5, which flexible supply line extendsfrom a non-illustrated control apparatus and in which so-called medialines extend to the handpiece 2 which pass through the handpiececoupling 5. Here there may be involved e.g. at least an electrical line,at least an electrical line, a light line, a water line, an air line ora water/air spray line.

The handpiece coupling 5 is preferably a quick-fastening coupling, inparticular in the form of a plug-in coupling or a plug-in/turn couplinghaving a coupling pin 8, in cross-section round, formed step-like and acoupling recess 9 which receives this coupling pin. With the presentexemplary embodiment, the coupling pin 8 extends forwardly from theconnection part 6 and the coupling recess 9 is arranged coaxially in therearward end region of the handpiece 2, whereby it opens rearwardly.

The main parts of the handpiece 2 are a grip sleeve 11 forming an outerbody of the handpiece 2, of more or less round cross-sectional shape,the cross-sectional size of which tapers somewhat forwardly, whereby theforward end region may diverge forwardly outwardly in the manner of acone. By these means there is provided a cross-sectional increase 12which improves the grippability of the handpiece 2 and prevents or makesmore difficult slipping of the operating hand holding the handpiece 2.

In the rearward region of the plug-in coupling or plug-in/turn couplingthere is provided a latching device 10, which upon coupling and upondecoupling can be manually overcome, having a radially elasticallyyieldingly arranged latching element for the manually overcomeablelatching of the coupling pin 8 in the coupling position.

The coupling recess 9 is arranged in the rearward end region of the gripsleeve 11, whereby the latching device 10 is effective between the gripsleeve 11 and the coupling pin 8.

In the grip sleeve 11 an oscillatory rod 13, preferably arrangedcoaxially, is so moveable radially or also axially against an elasticreturn force, and thus elastically yieldingly mounted, that it can carryout radial and preferably also axial and three-dimensional oscillationsor vibrations with a frequency in particular in the sonic or ultrasonicrange. For this mounting, a bearing sleeve 14 of elasticallycompressible material is placed in the grip sleeve 11 and axially fixed,in the forward end region or in the forward half of the grip sleeve 11,on the inner surface of which bearing sleeve at least one bearing ringis formed which closely surrounds the oscillatory rod 13 and therebymounts the rod, whereby due to the elasticity of the bearing sleeve 14,which is of e.g. rubber or plastics, in particular silicone, theoscillatory rod 13 can carry out radial and preferably also axial orthree-dimensional oscillations. In particular when the sleeve 14 isarranged only in the region of an oscillation generator—still to bedescribed, preferably arranged in the middle region of the oscillatoryrod 13—the sleeve 14 may be of sound absorbing or sound-soft material.

With the present configuration, the bearing sleeve 14 has two bearingrings 15 a, 15 b, in particular in the form of inwardly projectingrounded beadings in which the oscillatory rod 13 is mounted directly orby means of an attached part and which thus form radial bearings R1, R2.

For the axial positioning of the bearing sleeve 14 in the grip sleeve 11there may serve shoulder surfaces on the inner surface of the gripsleeve 11, on which shoulder surfaces counter-shoulder surfaces on theouter surface of the bearing sleeve 14 abut. With the presentconfiguration, the bearing sleeve 14 has at its outer surface one or tworadial projections 16 a, 16 b, having an axial spacing from one another,which are preferably each formed by means of a rounded annular beadingand which in the mounted position are latched into latch recesses 17 a,17 b, preferably formed by means of annular grooves, in the innersurface of the grip sleeve, in a sprung and thus elastic manner. Sincewith the present exemplary embodiment the grip sleeve 11 convergesforwardly in its cross-sectional size, the bearing sleeve—due to thisconvergence—finds a movement limitation in the manner of a stop in theforward direction, so that only a shoulder surface limiting a movementrearwardly is necessary. Instead of the forwardly converging conicity 14a there may also be provided an approximately cylindrically shape withan outer shoulder surface. The radial projections 16 a, 16 b or annularbeadings present fulfil the respective axial positioning of the bearingsleeve 14 very well, whereby the bearing sleeve 14 can be inserted fromthe rear into the grip sleeve 11, whereby the radial projections 16 a,16 b radially spring in and in the mounted end position self-actinglyelastically latch into the latch recesses 17 a, 17 b, whereby the axialpositioning of the bearing sleeve 14 is ensured. The length of thebearing sleeve 14 is made clear by means of the reference L.

For the axial positioning of the oscillatory rod 13 there are providedshoulder surfaces and counter-shoulder surfaces on the bearing sleeve 14and on the oscillatory rod 13, or on parts attached thereto, whichprevent a movement forwardly or also rearwardly (not shown) of theoscillatory rod 13. With the present configuration the at least one,here the forward, radial bearing ring 15 a, forms rearwardly a shouldersurface 18 on which the oscillatory rod 13 abuts indirectly with acounter-shoulder surface 19 on a part attached to the oscillatory rod13, which will be described further below.

For rearward positioning, the bearing sleeve 14 and/or the oscillatoryrod 13 may be bounded by an emplaced part designated overall as 21arranged rearwardly thereon, which preferably is likewise mountedradially or also axially elastically yieldingly in the grip sleeve 11and in the case of the present exemplary embodiment extends up to therearward end region of the grip sleeve 11 or of the handpiece 2 and isbounded rearwardly by means of an annular nut 22 screwed into the gripsleeve 11. For the radially elastically yielding mounting of theemplaced part 21 in the grip sleeve 11 there may be provided e.g. atleast one bearing ring 23 of elastically yielding material, such asrubber or plastics, which is arranged between the outer surface of theemplaced part 21 and the inner surface of the grip sleeve 11.

The oscillatory rod 13 is a sleeve-like body with the forward end regionof which the tool 13 is releaseably connected by means of the toolcoupling 4. The tool coupling 4 is preferably a per se known screwconnection having an inner thread and a preferably conical screw stop 20in the forward end region of the oscillatory rod 13 and a threaded pin 3a on the rearward end of an axially extending tool shaft 3 b, which inthe region of a thickening has a tool engagement element 3 c, e.g. a keysurface, in order that the screw connection can be tightened or releasedwith a special key which can be introduced from the fore.

A sickle-shaped tool section 3 d adjoins forwardly on the tool shaft 3b, which sickle-shaped tool section is first bent outwardly in a sickleshape to one side of the longitudinal middle axis 24 of the handpiece 2and ends on the other side of the longitudinal middle axis 24 in theform of a tool tip 3 e, extending in a straight manner, which isflattened or rounded, which is suited in particular for plaque removal.

The oscillatory rod 13 has a sleeve-like body, extending in a straightmanner, the annual wall 25 of which is preferably thicker in the forwardregion than in the rearward region. For additional axial positioning ofthe oscillatory rod 13, if appropriate, this may have in its rearwardregion, radially projecting pins 26 of round cross-section, whichmaintain an annular spacing, and engage the recesses 27 of the emplacedpart 21 and are elastically yieldingly positioned therein, in thelongitudinal direction and in the circumferential direction, by means ofrings 28 of elastically compressible material, e.g. rubber or plastics,surrounding the pins 26. This ensures that the rings 28 sit, with slightplay for movement or with slight elastic tensioning, both on therespectively associated pin 26 and also the associated recess 27.

The associated oscillatory drive is, with the present exemplaryembodiment, formed by means of a pneumatic oscillation generator 31which is arranged in the middle region of the oscillatory rod 13 and isformed in a per se known manner by means of an oscillatory sleeve 32,surrounding the oscillatory rod 13 with radial play for movement, andholes 33 obliquely penetrating the annular wall in the region of theoscillatory sleeve. An axial range of movement for the oscillatorysleeve 32 is bounded by means of rings 34, e.g. O-rings, arranged to thetwo sides of the oscillatory sleeve 32 with axial spacing therefrom,which rings each sit in an annular groove in the outer surface of theoscillatory rod 13.

The oscillation generator 31 is surrounded by a damping sleeve 35, withradial spacing, which may be supported axially and/or radially on theoscillatory rod 13 or on the emplaced part 21. With the presentconfiguration, a rearward hollow cylindrical end section of the dampingsleeve 35 engages over a forward end section of the emplaced part 21,whereby between these parts there may be arranged a sealing and/orsupport ring 37 in an annular groove. Further, the damping sleeve 35 mayabut on the emplaced part 21 with an inner surface 36 and ring 37 andthereby be limited rearwardly. The damping sleeve 35 may extendforwardly up to the bearing ring 15 a, whereby the sleeve may form thecounter-shoulder surface 19. In the forward end region, the dampingsleeve 35 is tapered relative to its rearward cross-section. In therearward region the damping sleeve 35 may be mounted in the bearingsleeve 14, preferably in the bear ring 15 b.

A control device is associated with the oscillation generator 31 forreducing or increasing its power. By these means its power or theintensity of the vibration and the size of the amplitudes can beselectively reduced or increased and thus set. Thereby there may beprovided a power regulator 41 for automatic regulation of a preferablyconstant power and/or a manually settable control device 42 with whichthe power or the drive pressure deliverable to the oscillation generator31 is variable and thereby reducible or increasable in steps orcontinuously. For activating the control device 42 there is provided asetting device 43, preferably in the rearward end region of thehandpiece 2 or of the grip sleeve 11. By these means the power of thetreatment instrument 1 can be adapted to the work to be accomplished,e.g. coarse or fine working or coarse, medium and fine working, oradapted to different kinds of treatment and/or of the material to betreated and/or with regard to the shape and/or size and/or coarser andfiner or coarser, middle and/finer effect of different available tools3.

The manually actuable setting device 43 has a setting member 44 which isarranged to be externally manually accessible and to be axially orcircumferentially adjustable on the grip sleeve 11, and which settingmember is in drive connection with the control device 42 and/or formsthe control device. With the present configuration, the setting memberis a setting sleeve which surrounds the grip sleeve 11 in the rearwardregion of the handpiece and is preferably arranged inset in an annularrecess 45. With the present exemplary embodiment, the control device 42has a control valve 46 for the purpose of controlling the air pressurep1 effective at the oscillation generator 31. Here, the setting member44 is connected with a valve slider 48, directly when the setting memberis axially moveable or by means of a transmission 47 which converts arotary movement of the setting member into an axial movement, whichvalve slider controls the size of the valve opening 49 in dependenceupon the setting of the setting member 44. The valve opening 49 islocated in a compressed air supply line 51, here downstream of thehandpiece coupling 5 in the region of a transversely running anglechannel. For reducing the oscillation power the valve slider 48 isdisplaced with the setting device 43 in the sense of a reduction of thevalve opening 49, so that the valve opening 49 reduces the pressure p1acting at the oscillation generator 31 in the sense of an adjustablethrottle. For increasing the power, the valve opening 49 is, in theopposite way, increased, whereby the larger applied pressure p1 is set.The return movement of the setting member 44 can be effected by means ofa return spring 52 which biases a push rod 53, acting on the valveslider 48, against an oblique or curve surface 54 a which is arranged onan attached part of the setting member 44 projecting into the handpiece2.

It is advantageous, in addition to or in place of the control device 42for setting the applied pressure p1, to provide an automatic pressureregulation device having a pressure regulation valve 55 whichindependently of the available operating pressure p2 in the supply line51 sets a substantially constant effective pressure p1. By these meanseven with considerable tolerances or differences of the operatingpressure p2, there is attained in substance the same working conditionsand an approximately uniform power of intensity of the tool 3, e.g. uponconnecting the treatment instrument to supply lines 7 having differentoperating pressures p2, in particular from different manufacturers.

Both in the presence of a control valve 46 and also of a regulationvalve 55, the valve slider 48 is arranged in the supply line, here inthe axis-parallel supply line section 51 b, preferably mounted to belongitudinally displaceable therein. The valve opening 49 can becontrolled by means of an end edge of the valve slider 48.

In the present exemplary embodiment there are provided a control deviceor a manual setting device 43 in combination with a pressure regulatingvalve 55. On its one end side the valve slider 48 is acted upon by theeffective pressure p1 and on its other end side is oppositely biasedinto its opened position by means of a pressure spring, which may be thereturn spring 52. In the present configuration, the valve slider 48 is around or non-round pot-shaped sleeve having a floor wall 48 a at its endaway from the oscillation generator 31. The valve opening 49 is arrangedin the radially inwardly lying circumferential wall 48 b co-operatingwith the radial section of the supply line 51 b. In the opened position,the valve slider 48 is biased by means of the spring against a stop 48c, here against a socket piece. A spring spike 48 d extends from thevalve slider 48 rearwardly, on which spring spike the pressure spring 52sits and is supported against a rearward counter bearing, here againstthe push rod 53.

It is advantageous to so form the oscillatory rod 13 that its mass canbe reduced or increased, or to provide a plurality of oscillatory rods13 of different masses, so that an oscillatory rod 13 with the desiredmass can be set or installed. By these means, through an alteration ofthe mass of the oscillatory rod 13 or through an exchange of theoscillatory rod 13, there can be attained a desired generator powerand/or a favourable oscillatory behaviour of the oscillatory rod 13,whereby the power available can be better exploited.

A plurality of oscillatory rods 13 of different masses can be formedthrough the making of oscillatory rods 13 of the same or differentdimensions and/or of materials of differing relative densities, wherebythe oscillatory rods 13 may be formed with the same or differenttransverse and/or longitudinal dimensions.

With the present exemplary embodiment, the different mass is attained bymeans of an attachment part 61 of the oscillatory rod 13, which can beattached, in particular releaseably, fixedly, i.e. non-moveably, or ispermanently attached, preferably in the rearward end region of theoscillatory rod 13. Hereby, different masses can be attained in that anoscillatory rod 13 without attachment part 61 and an oscillatory rod 13with attachment part 61 is provided. Further variations of mass can beachieved in that a plurality of attachment parts 61 of differing massesare provided, which can be selectively connected with the oscillatoryrod 13. Here, there may likewise be involved attachment parts 61 ofmaterials of differing densities and/or with differing transversedimensions and/or longitudinal dimensions.

With the present exemplary embodiment there is provided an attachmentpart 61 which, with a tapered hollow cylindrical plug-in pin 61 a at itsforward end, is inserted into the sleeve body of the oscillatory rod 13from the rear, releasably or non-releasably and can be positionedagainst an unintended displacement, e.g. by means of radial clampingeffect or press fitting. The attachment part 61 projects beyond theoscillatory rod 13 rearwardly with its thickened main body part 61 bwhich in its cross-sectional shape is preferably adapted to thecross-sectional shape and size of the annular wall 25. The attachmentpart 61 is of a material preferably of greater specific density than thematerial of the oscillatory rod 13. The oscillatory rod 13 is preferablyof e.g. corrosion resistant alloyed steel or a copper-beryllium alloy(CuBe). The attachment part or parts 61 may e.g. be of another metal oranother steel alloy or hard metal. Hard metal is a sintered materialwhich consists for the most part of tungsten carbide as hard materialand cobalt as a binder. The hard metal type K10, classified inaccordance with ISO, is very well suited for the present purpose. AsFIG. 7 shows, the attachment part 61 may be formed by means of a sleevewhich sits in the wall 25 in the above-described manner. Thereby, theoscillatory rods in accordance with FIGS. 6 and 7 may project rearwardlybeyond an oscillatory rod 13 according to FIG. 6 or the wall 25 may beextended rearwardly to end flush with the sleeve of the attachment part61. Both configurations show examples for an increase of mass of theoscillatory rod 13 without an increased of width.

Two or more oscillatory rods 13 of different masses can by means ofselective installation replace a power regulator 41 or a control device42 since they make it possible through purposive installation orexchange to set different powers or oscillation widths or amplitudes.When, in addition to a power regulator 41 or a control device 42, two ormore oscillatory rods 13 of different masses are available, which can beinstalled in a workshop or by the user, by means of the installation orexchange the setting of the power or the oscillation width can bedisplaced in the sense of an increase (heavier oscillatory rod 13) or areduction (lighter oscillatory rod 13).

The grip sleeve 11 and preferably also the bearing sleeve 14 projectbeyond the forward end of the oscillatory rod 13 or the tool coupling 4axially by an amount indicated by a, whereby they surround the toolshaft 3 b with a radial spacing and preferably extend up to the rearwardend region of the sickle-shaped curvature.

The internal form of the bearing sleeve 14 is adapted to thecross-sectional shape and size of the oscillatory rod 13 and of thedamping sleeve 35, whereby in the regions near the bearing rings 15 a,15 b there may be arranged an annular gap between the bearing sleeve 14and the oscillatory rod 13 and the damping sleeve 35. By these means,the bearing sleeve 14 is formed in its rearward region with a lesserwall thickness than in its forward region, in which it is thickenedcorrespondingly to the cross-sectional reduction of the forward regionof the damping sleeve 35 and of the oscillatory rod 13.

In functional operation, the oscillation generator 31 and the handpiece2 generate operational noises which are emitted to the surroundings assound generated through the vibration of the oscillatory sleeve 32 or assolid-borne is sound. In the region of the oscillation generator 31 theoperating noise is damped by means of the bearing sleeve 14 additionallyto the damping effect of the damping sleeve 35, which bearing sleevesurrounds the oscillation generator 31 and preferably projects beyond itrearwardly. The damping effect is additionally damped by means of theannular gap 65 a which extends at least in the region of the oscillationgenerator 31 between the bearing sleeve 14 and the damping sleeve 35. Itis also advantageous to provide an annular gap 65 b in the axial regionof the oscillation generator 31 between the grip sleeve 11 and thebearing sleeve 14, which annular gap makes possible an additionaldamping effect. This annular gap 65 b may be formed by means of anannular indentation in the outer surface of the bearing sleeve 14 or inthe inner surface of the grip sleeve 11. It may be arranged between theradial projections 16 a or recesses 17 a. The damping effect, actingover the overall length L of the bearing sleeve 14, is increased bymeans of its elastically compressible material.

In the region a, in which the grip sleeve 11 and/or the bearing sleeve14 may surround the oscillatory rod 13 or the tool shaft 3 b, a sounddamping is likewise attained, whereby in particular the solid-bornesound emitted from the tool coupling 4 and from the tool shaft 3 b isdamped. Tests have shown that by means of the extension a a sounddamping of about 15 dB can be attained and this even without a coatingof the inner surface with an elastically yielding material. The rearwardradial bearing R1 is preferably arranged between the radial annularbeadings 16 a, 16 b or in the region of the annular gap 65 b.

In functional operation, the oscillatory rod 13 on the one hand and thetool 3 on the other hand carry out, due to the elongate construction,transversely directed oscillations (FIG. 5) which develop in a sinecurve form, i.e. are directed oppositely to one another in longitudinalsections L1, L2, L3 following one another. Between the longitudinalsections L1, L2, L3 there are oscillation nodes S1, S2, S3 in which theamplitudes are practically zero. Between the oscillation nodes S1, S2,S3 amplitude peaks A1, A2 are located in the middle. The rearwardoscillation node S1 is at a spacing L4 from the rearward end of theoscillatory rod 13, which is about one quarter of its length L and ispreferably arranged in the region of the rearward elastic radial bearingR1. The forward—referring to the oscillatory rod 13—oscillation node S2is preferably located in the region of the forward elastic radialbearing R2. The forward oscillation node S3 is located preferably in themiddle region of the tool section 3 d which is shaped to be arc-like.The longitudinal position of the rearward oscillation node S1 can,through the mass and its center of gravity SP1, taking into account thecenter of gravity SP2 of the remaining body of the oscillatory rod 13,be varied and preferably so adapted that the rearward oscillation nodeS1 is located in the region of the rearward elastic radial bearing R1.

The exemplary embodiments according to FIGS. 8 to 10, in which the sameor similar parts are provided with the same reference signs, differ inthe following details of configuration.

With the configuration according to FIG. 8 there is provided a gripsleeve 11 which is longitudinally divided in the region of the toolcoupling 4, so that there are provided a rearward sleeve part 11 a and aforward, cap-like or elongated grip sleeve part 11 b, which areconnected with one another by means of a releasable coupling 66, wherebythe forward grip sleeve part 11 b surrounds the tool shaft 3 b withradial spacing and extends into the transition region of thesickle-shaped tool section 3 d. The releasable coupling 66 is, inaccordance with FIG. 5, formed by means of a screw connection, wherebythe rearward grip sleeve part 11 a has an inner threading at its forwardend, into which the forward grip sleeve part 11 b is screwed with anexternal threading at its rearward end and tightened against a stop 67.In its forward end region the oscillatory rod 13 is mounted elasticallyyieldingly and centered in a bearing ring 68, emplaced in the forwardend region of the rearward grip sleeve part 11 a, of elasticallycompressible and preferably also sound absorbing material, such asrubber or plastics, e.g. silicone. The bearing ring 68 may be of anon-elastic material, e.g. steel or a steel alloy, when an inner bearingring 68 a of elastically yielding material, e.g. an O-ring, is arrangedtherein, in which the oscillatory shaft is elastically yieldinglymounted.

The exemplary embodiment according to FIG. 9 differs from that accordingto FIG. 8 in that the grip sleeve part 11 b, with regard to its externalform and if applicable also its internal form, is forwardly tapered ande.g. screwed into the bearing ring 68. The external, preferablycone-like tapering improves visual observation in functional operation.Further, the illumination of the treatment site is improved by means ofan illumination device 71 which is still to be described. The bearingring 68 can be bounded against an ejection movement by means of a stepshoulder 68 b in the bearing bore in the rearward grip part section 11a, as a stop.

With the exemplary embodiment according to FIG. 10, the coupling 66 isformed by means of a plug-in connection or a bayonet connection, wherebythe forward grip part section 11 b preferably engages over the forwardend of the rearward grip part section 11 a. The forward grip sleeve part11 b may be of rigid or elastically deformable or compressible or soundwave absorbing or sound-soft material, e.g. of corrosion resistantmetal, alloy steel, rubber or plastic, e.g. silicone. In particular whenthe grip sleeve part 11 b is of elastically yielding material, thecoupling 66 may also be formed by means of a latching device, havingradially inwardly directed latch noses or a latch ring at the rearwardend of the grip part section 11 b which latch, preferably releasably,into a latching groove on the rearward grip part section 11 a uponplugging together.

The configuration according to FIG. 10 makes clear a sound-wave dampingand/or reflecting structure 72 on the inner surface of the forward grippart section 11 b. Such a structure can be formed e.g. by means offorwardly convergent or oblique or roundly formed annular surfaces whichreflect to the sound inwardly. Here, the inner surface may have asaw-tooth-like form. As already with the exemplary embodiment accordingto FIG. 1, with a grip part section 11 b its inner surface can also becoated or occupied with an elastically compressible material.

The handpiece 2 may have the illumination device 71, having at least onelight outlet window 73, at the forward end of the handpiece 2. The lightoutlet window 73 is preferably arranged in the bearing sleeve 14 or 68.It is advantageous to provide at least two light outlet windows 73 whichin particular are provided on the two sides of a longitudinal middleplane E in which the free end region of the tool section 3 d is locatedor in the case of a transverse offset extends approximately parallel,c.f. FIG. 2. In the present exemplary embodiment, the at least one lightoutlet window 73 is formed by means of a light conductor 74 whichextends at least partly longitudinally through the bearing sleeve 14.Thereby, the light conductor 74 may be fixedly embedded in the bearingsleeve 14 or the bearing sleeve 14 may have, for receiving the lightconductor 74, a pre-fabricated hole or a pre-fabricated inwardly opengroove 75. As can be seen from FIG. 3, the at least one light conductor74 extends from an approximately middle position to the outer region ofthe handpiece 2, whereby it continues further longitudinally through thebearing sleeve. Preferably there are provided two light conductors 74,in mirror-image arrangement, which branch from a common inlet piece. Thelight can supplied to the rearward end of the at least one lightconductor 74 in various ways. There may extend in the region of thehandpiece coupling 5 a rearward light conductor, coaxially through thehandpiece coupling 5—here through the coupling pin 8—out of which thelight is introduced into the light conductor 74. It is also possible toprovide a light source, in particular a lamp, in the forward end regionof the coupling pin 8, which is connected to an electrical supplycircuit which extends through the supply line. The light conductor 74may extend to a light conductor ring 76 emplaced or embedded in thebearing ring 68 from which light conductor ring one or more lightconductor sections 77 may extend forwardly to the light outlet windows73.

In functional operation the compressed air, delivered through the supplyline 51, flows through the oscillation generator 31 from the inside tothe outside. The used air flows from the inner chamber of the dampingsleeve 35 into an annular free space 78 of the handpiece 1 rearwardly upto the region of the plug-in/turn coupling 5 from where it passesthrough the hollow cylindrical or step-like hollow cylindrical jointbetween the coupling recess 9 and the coupling pin 8 transversely sealedoff, and extends in the coupling pin 8 as discharge line 79 or channelrearwardly, as is per se known. A further supply line 81 for a treatmentfluid, e.g. air or water or a spray formed therefrom, can likewiseextend axially in the coupling pin 8, pass through its cylindrical jointat 82 in a radially sealed manner and then extend axially furtherforwardly, e.g. as tube 83, and be connected centrally to a supply pipe84 behind the inlet piece or the forking of the light conductor 73,which supply pipe extends forwardly concentrically in the oscillatoryrod 13 and stands in connection in sealed manner with a longitudinalchannel 85 in the tool 3. An exit opening in the tool 3 for thelongitudinal channel 85, directed towards the treatment site, is notshown but is however present and is known per se.

With the exemplary embodiment according to FIG. 11, the forward gripsleeve part 11 b is axially displaceably mounted, indirectly ordirectly, in the rearward grip sleeve part 11 a and by means of theforce of a spring 86 is acted upon into its pushed out position, inwhich its pushing movement is limited by means of a stop 87. As FIG. 11shows, the forward grip sleeve part 11 b may be mounted in an innerannular recess 88 in the bearing ring 68 which thus forms a longitudinalguide. The shoulder surface 89 of a tapering of the annular recess 88can form the stop 87, which co-operates with the shoulder surface of aradial annular attachment in the rearward end region of the grip sleevepart 11 b.

With the exemplary embodiment according to FIG. 11 there is additionallyprovided an illumination device 71, similar to the configurationaccording to FIG. 9, having one, more or e.g. three light outlet windows73 arranged distributed on the circumference, to which in each case alight conductor section 77 extends which starts from a light conductorring 76 which is emplaced or embedded in the bearing ring 68. With thisconfiguration, the forward grip sleeve part 11 b can be pushed in, forreducing the projection a, e.g. in order to create more free space inthe mouth of the patient or to facilitate the access to the engagementelement 3 c.

The plug-in/turn coupling 5 makes possible an unrestricted turning ofthe treatment instrument 1 around its longitudinal axis relative to theconnection part 6, whereby in any rotational position the passage of themedia in a sealed manner is ensured.

For switching on the treatment instrument 1 or the oscillation generator31 for functional operation there is provided a switch, here in the formof a switching valve in the supply line 51, which can be actuated withthe operating hand or a foot of the operating person.

What is claimed is:
 1. A medical and/or dental instrument comprising: a rod-like handpiece comprising a forward end region releasably coupled to a tool by a tool coupling the rod-like handpiece further comprising a rearward end region releasably coupled to a connection part by a handpiece coupling, the handpiece comprising a grip sleeve which forms an outer body of the handpiece, an oscillatory rod which extend longitudinally in the grip sleeve and is elastically yieldingly mounted therein, a pneumatic oscillation generator for transmitting oscillations to the oscillatory rod, and an inner sleeve surrounding the oscillation generator and disposed in the grip sleeve, wherein the inner sleeve comprises an elastically compressible or a sound absorbing material.
 2. The medical and/or dental instrument according to claim 1, wherein the sleeve is radially supported on an inner surface of the grip sleeve.
 3. The medical and/or dental instrument according to claim 2, wherein the sleeve surrounds an inner sleeve which, in turn, in an axial region of the oscillation generator, surrounds the oscillatory rod.
 4. The medical and/or dental instrument according to claim 2, wherein the sleeve forms a radial bearing for the oscillatory rod.
 5. A medical and/or dental instrument according to claim 4, wherein the sleeve extends up to a forward end of the grip sleeve.
 6. The medical and/or dental instrument according to claim 1, wherein in a region of the oscillation generator, an outer surface of the sleeve is spaced apart from the inner surface of the grip sleeve to define an annular gap.
 7. A medical and/or dental instrument comprising a rod-like handpiece comprising a forward end region to which a tool is releasably coupled by a tool coupling, the handpiece further comprising a rearward end region releasably coupled to a connection part by a handpiece coupling, the handpiece comprising: a grip sleeve forming an outer body of the handpiece, an oscillatory rod which extends longitudinally in the grip sleeve and is elastically yieldingly mounted therein, a pneumatic oscillation generator for transmitting oscillations to the oscillatory rod, and a sleeve surrounding the oscillation generator wherein at least one of the grip sleeve and/or the sleeve which is radially supported on an inner surface of the grip sleeve are made of elastically compressible or sound absorbing material, and project or projects forwarding beyond the tool coupling.
 8. The medical and/or dental instrument according to claim 7, wherein the sleeve is made of rubber or plastic.
 9. The medical and/or dental instrument according to claim 7, wherein the sleeve is made of silicone.
 10. The medical and/or dental instrument according to claim 7, wherein the grip sleeve extends forwardly beyond the forward end region of the handpiece.
 11. The medical and/or dental instrument according to claim 10, wherein a cross-sectional of the grip sleeve and/or of the sleeve that projects forwardly beyond the tool coupling has a truncated conical shape.
 12. The medical and/or dental instrument according to claim 7, wherein a portion of the grip sleeve and/or the sleeve section projecting beyond the tool coupling comprises a separate component which is connected with the grip sleeve or sleeve by a releasable coupling.
 13. The medical and/or dental instrument according to claim 12, wherein the releasable coupling comprises a connection selected from the group consisting of a screw connection, a bayonet fastening or a latch connection.
 14. The medical and/or dental instrument according to claim 7, wherein the inner surface of the grip sleeve has a structure for reflecting sound waves inwardly.
 15. The medical and/or dental instrument according to claim 7, further comprising a plurality of grip sleeve sections and/or sleeve sections which can be selectively mounted, and which differ with regard to their length. 